antiquated vs antediluvian

antiquated is not a noun while antediluvian is a noun.

Word	Noun	Adjective	Verb	Adverb
antiquated	No	Yes	No	No
antediluvian	Yes	Yes	No	No

As adjectives, antiquated and antediluvian are synonyms defined as:

antiquated and antediluvian: so extremely old as seeming to belong to an earlier period

Other synonyms of antiquated include archaic.

antiquated (noun)	antediluvian (noun)
	a very old person
	any of the early patriarchs who lived prior to the Noachian deluge

antiquated (adjective)	antediluvian (adjective)
so extremely old as seeming to belong to an earlier period	of or relating to the period before the biblical flood
	so extremely old as seeming to belong to an earlier period